fix universal: use std::addressof in implementation of OptionalRef

Fixes #1208
Tests: протестировано CI

Additionally, explicit `operator!=` has been removed.

---

Pull Request resolved: #1209

Co-authored-by: antoshkka <antoshkka@userver.tech>
Co-authored-by: antoshkka <antoshkka@userver.tech>
commit_hash:d6ee51c8c3e53d4f7a599d1bb6a8cebf3c0c7451

Author: 2 people

universal/include/userver/utils/optional_ref.hpp

@@ -3,6 +3,7 @@
 /// @file userver/utils/optional_ref.hpp
 /// @brief @copybrief utils::OptionalRef
 
+#include <memory>
 #include <optional>
 #include <type_traits>
 
@@ -35,7 +36,7 @@ class OptionalRef {
     constexpr OptionalRef(const OptionalRef&) noexcept = default;
     constexpr OptionalRef& operator=(const OptionalRef&) noexcept = delete;
 
-    constexpr OptionalRef(T& other) noexcept : data_(&other) {}
+    constexpr OptionalRef(T& other) noexcept : data_(std::addressof(other)) {}
 
     // Forming a reference to a temporary is forbidden
     explicit constexpr OptionalRef(const T&&) = delete;
@@ -101,12 +102,7 @@ class OptionalRef {
             "Attempt to initialize non-const T from a const optional value"
         );
 
-        if (!other) {
-            return nullptr;
-        }
-
-        auto& value = *other;
-        return &value;
+        return other.has_value() ? std::addressof(*other) : nullptr;
     }
 
     T* const data_ = nullptr;
@@ -120,11 +116,6 @@ constexpr bool operator==(OptionalRef<T> lhs, OptionalRef<U> rhs) noexcept {
     return *lhs == *rhs;
 }
 
-template <class T, class U>
-constexpr bool operator!=(OptionalRef<T> lhs, OptionalRef<U> rhs) noexcept {
-    return !(lhs == rhs);
-}
-
 }  // namespace utils
 
 USERVER_NAMESPACE_END

universal/src/utils/optional_ref_test.cpp

@@ -2,6 +2,10 @@
 
 #include <gtest/gtest.h>
 
+#include <optional>
+
+#include "overloaded_address_operator_test.hpp"
+
 USERVER_NAMESPACE_BEGIN
 
 namespace {
@@ -29,6 +33,25 @@ TEST(OptionalRef, Constructions) {
     static_assert(!std::is_constructible_v<OptionalRef<short>, int&>);
 }
 
+TEST(OptionalRef, ConstructionsAddressof) {
+    {
+        utils::OverloadedAddressOperator over;
+        utils::OptionalRef<utils::OverloadedAddressOperator> ref(over);
+    }
+    {
+        utils::OverloadedAddressOperator over{};
+        utils::OptionalRef<utils::OverloadedAddressOperator> ref{over};
+    }
+    {
+        std::optional<utils::OverloadedAddressOperator> over(std::in_place);
+        utils::OptionalRef<utils::OverloadedAddressOperator> ref(over);
+    }
+    {
+        std::optional<utils::OverloadedAddressOperator> over{std::in_place};
+        utils::OptionalRef<utils::OverloadedAddressOperator> ref{over};
+    }
+}
+
 TEST(OptionalRef, Values) {
     int a1_val = 1;
     int b1_val = 1;